ios - swift 'does not have a member named'

Question

这个问题有解决办法吗？

class ViewController : UIViewController {
    let collectionFlowLayout = UICollectionViewFlowLayout()
    let collectionView = UICollectionView(frame: CGRectZero, collectionViewLayout: collectionFlowLayout)
}

xcode 给我以下错误

ViewController.swift: 'ViewController.Type' does not have a member named 'collectionFlowLayout'

我可以使它成为可选的并在 init 方法中初始化它，但我正在寻找一种方法使 collectionview 成为 let 而不是 var

Answer 1

您可以在初始化程序中为常量成员变量分配初始值。无需将其设为 var 或可选。

class ViewController : UIViewController {
    let collectionFlowLayout = UICollectionViewFlowLayout()
    let collectionView : UICollectionView

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?)
    {
        self.collectionView = UICollectionView(frame: CGRectZero, 
                                collectionViewLayout: self.collectionFlowLayout);

        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil);
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}